I am the author. Flash support in Chrome is going away soon (but even if it didn't) I am not going to be publishing any code with support for that crap baked in. However, it is understandable if you disagree.
Re: referrer option, as I explained, it's a nop. So no point in having extra code for that there either (I really should remove it).
I had to use Flash two weeks ago to get a food handler’s permit online due to pandemic and terrible horrible choice from a list of 20 options, so I am unusually positioned to disagree from personal basis. I do agree that it should die and I can’t wait for it to do so either!
Re: referrer option, as I explained, it's a nop. So no point in having extra code for that there either (I really should remove it).